ichni_Official/Assets/Scripts/Menu/MenuInformationRecorder.cs

using System;
using System.Collections;
using System.Collections.Generic;
using Sirenix.OdinInspector;
using UnityEngine;

namespace Ichni.Menu
{
    public class MenuInformationRecorder : SerializedMonoBehaviour
    {
        public static MenuInformationRecorder instance;
        public Dictionary<ChapterSelectionUnit, SongSelectionRecord> songSelectionRecords;

        private void Awake()
        {
            if (instance == null)
            {
                instance = this;
                songSelectionRecords = new Dictionary<ChapterSelectionUnit, SongSelectionRecord>();
            }
            else
            {
                Destroy(gameObject);
            }
        }

        public SongSelectionRecord GetRecordOfThisChapter()
        {
            ChapterSelectionUnit currentChapter = ChapterSelectionManager.instance.currentChapter;
            if (songSelectionRecords.TryGetValue(currentChapter, out SongSelectionRecord record))
            {
                return record;
            }
            else
            {
                return new SongSelectionRecord(currentChapter.songs[0], currentChapter.songs[0].difficultyDataList[0]);
            }
        }
    }

    public class SongSelectionRecord
    {
        public SongItemData song;
        public int difficultyIndex;
        
        public SongSelectionRecord(SongItemData song, DifficultyData difficulty)
        {
            this.song = song;
            difficultyIndex = song.difficultyDataList.IndexOf(difficulty);
        }
    }
}